In recent years, a vehicle that incorporates a power storage device (for example, a secondary battery, a capacitor, etc.) and runs with driving force generated from electric power stored in the power storage device is attracting attention as an environmentally friendly vehicle. Examples of such vehicles include an electric vehicle, a hybrid vehicle, a fuel-cell vehicle, etc.
Such a power storage device is generally configured to output a desired voltage by stacking a plurality of battery cells in series or in parallel. If a malfunction such as a disconnection or a short circuit occurs in these battery cells, the power storage device may not function properly. It is therefore necessary to detect a malfunction in the battery cells.
Japanese Patent Laying-Open No. 2009-189209 (PTL 1) discloses a power supply apparatus for a vehicle wherein a connecting portion provided between a power storage device and an electric load is brought into a connected state in response to a vehicle start-up instruction, and the presence or absence of a disconnection in a path for supplying operating current from the power storage device to the electric load is diagnosed based on an output from a current sensor obtained when electric power is consumed by the electric load.